Science (English Medium) Class 12 - CBSE Question Bank Solutions for Chemistry

On reaction with \[\ce{Cl2}\], phosphorus forms two types of halides ‘A’ and ‘B’. Halide A is yellowish-white powder but halide ‘B’ is colourless oily liquid. Identify A and B and write the formulas of their hydrolysis products.

White phosphorus reacts with chlorine and the product hydrolyses in the presence of water. Calculate the mass of \[\ce{HCl}\] obtained by the hydrolysis of the product formed by the reaction of 62 g of white phosphorus with chlorine in the presence of water.

Using valence bond theory, explain the following in relation to the complexes given below:

\[\ce{[Mn(CN)6]^{3-}}\]

(i) Type of hybridisation.
(ii) Inner or outer orbital complex.
(iii) Magnetic behaviour.
(iv) Spin only magnetic moment value.

Using valence bond theory, explain the following in relation to the complexes given below:

\[\ce{[Co(NH3)6]^{3+}}\]

(i) Type of hybridisation.
(ii) Inner or outer orbital complex.
(iii) Magnetic behaviour.
(iv) Spin only magnetic moment value.

Using valence bond theory, explain the following in relation to the complexes given below:

\[\ce{[Cr(H2O)6]^{3+}}\]

(i) Type of hybridisation.
(ii) Inner or outer orbital complex.
(iii) Magnetic behaviour.
(iv) Spin only magnetic moment value.

Using valence bond theory, explain the following in relation to the complexes given below:

\[\ce{[FeCl6]^{4-}}\]

(i) Type of hybridisation.
(ii) Inner or outer orbital complex.
(iii) Magnetic behaviour.
(iv) Spin only magnetic moment value.

Mark the correct order of decreasing acid strength of the following compounds.

(a)
(b)
(c)
(d)
(e)

Out of o-nitrophenol and o-cresol which is more acidic?

Assertion: o-Nitrophenol is less soluble in water than the m- and p-isomers.

Reason: m- and p- Nitrophenols exist as associated molecules.

Cannizaro’s reaction is not given by ______.

Which product is formed when the compound  is treated with concentrated aqueous \[\ce{KOH}\] solution?

Compounds A and C in the following reaction are:

\[\ce{CH3CHO ->[(i) CH3MgBr][(ii) H2O] (A) ->[H2SO4, Δ] (B) ->[Hydroboration oxidation] (C)}\]

Which of the following compounds do not undergo aldol condensation?

(i) \[\ce{CH3 - CHO}\]

(ii)  

(iii)  \[\begin{array}{cc}
\phantom{}\ce{O}\\
\phantom{}||\\
\ce{CH3 - C - CH3}
\end{array}\]

(iv) \[\begin{array}{cc}
\phantom{}\ce{CH3}\\
|\phantom{...}\\
\ce{CH3 - C - CHO}\phantom{..}\\
|\phantom{...}\\
\phantom{}\ce{CH3}\\
\end{array}\]

Which of the following conversions can be carried out by Clemmensen Reduction?

(i) Benzaldehyde into benzyl alcohol

(ii) Cyclohexanone into cyclohexane

(iii) Benzoyl chloride into benzaldehyde

(iv) Benzophenone into diphenyl methane

Why is there a large difference in the boiling points of butanal and butan-1-ol?

What product will be formed on reaction of propanal with 2-methylpropanal in the presence of \[\ce{NaOH}\]? What products will be formed? Write the name of the reaction also.

Compound ‘A’ was prepared by oxidation of compound ‘B’ with alkaline \[\ce{KMnO4}\]. Compound ‘A’ on reduction with lithium aluminium hydride gets converted back to compound ‘B’. When compound ‘A’ is heated with compound B in the presence of \[\ce{H2SO4}\] it produces fruity smell of compound C to which family the compounds ‘A’, ‘B’ and ‘C’ belong to?

Why are carboxylic acids more acidic than alcohols or phenols although all of them have hydrogen atom attached to a oxygen atom \[\ce{(-O-H)}\]?

Assertion: The α-hydrogen atom in carbonyl compounds is less acidic.

Reason: The anion formed after the loss of α-hydrogen atom is resonance stabilised.

Assertion: Aromatic aldehydes and formaldehyde undergo Cannizaro reaction.

Reason: Aromatic aldehydes are almost as reactive as formaldehyde.